1. Field of the Invention
The present invention relates to a back illuminated photodiode array and a method of manufacturing the same.
2. Related Background Art
Three-dimensional packaging technologies have been studied in many fields. Conventionally, in a three-dimensional packaging, a hole penetrating upper and lower planes of a substrate is formed, and an electrode at one plane side is drawn out through this hole to the other plane side.
In such a through-hole formation process in the three-dimensional packaging, ICP plasma etching is usually used. However, the thickness of a wafer is as thick as about 300 μm to 400 μm, and thus a considerable amount of time is required to form a through-hole. Moreover, an etching process by use of an ICP plasma etching apparatus is performed once per wafer, and thus multiple pieces of wafers cannot be processed simultaneously. As a result, it requires a large amount of time to form a through-hole for one piece of wafer. Therefore, by use of this etching technology, a product that can be formed only by small quantities at one time of etching, in other words, a large area photodiode array cannot be industrially mass-produced. For example, formation of several large area photodiode arrays by taking several hours per wafer to form the hole is not approved commercially.